seccomp: add __NR_fstat64 for printf()

At least on some 32-bit systems glibc uses fstat64 instead of fstat.

util/Seccomp.c

@@ -259,6 +259,9 @@ static struct sock_fprog* mkFilter(struct Allocator* alloc, struct Except* eh)
 
         // printf()
         IFEQ(__NR_fstat, success),
+        #ifdef __NR_fstat64
+            IFEQ(__NR_fstat64, success),
+        #endif
 
         // for setting IP addresses...
         // socketForIfName()